1. Field of the Invention
This invention relates to rinse cycle fabric softener compositions. More particularly it relates to aqueous liquid microemulsion fabric softener compositions that are clear, i.e., transparent even when highly concentrated.
2. Description of Related Art
U.S. Pat. No. 3,892,669 issued to A. A. Rapisarda et al. relates to a clear aqueous fabric softening composition containing a solubilized tetra alkyl quaternary ammonium salt having two short-chain alkyl and two long-chain alkyl groups, about 5% to about 25% of the latter having methyl and ethyl branching on the 2-carbon atom. Solubilization is effected by the presence of solubilizers comprising aryl sulfonates, diols, ethers, low molecular weight quaternaries, sulfobetaines, taurines, sulfoxides and non-ionic surfactants.
U.S. Pat. No. 4,149,978 issued to P. C. E Goffinet describes textile treatment compositions comprising a water-soluble fabric softener and a C12-C40 hydrocarbon optionally together with a water-soluble cationic surfactant. The preferred fabric softeners are quaternary ammonium salts having two C10-C22 alkyl chains.
U.S. Pat. No. 4,351,737 issued to S. Billenstein describes and claims softening concentrates containing 30-70% of a cationic softener, 5-50% of a non-ionic softener, 5-20% of a non-ionic dispersing agent, 5-30% of a C1 to C3 alkanol, 5-30% of liquid glycol, polyglycol or alkyl ether and water and optionally perfume and dyestuffs.
The fabric softener prepared according to this patent is alleged to be easily dispersible in water.
U.S. Pat. No. 4,569,800 issued to K. D. Stanley et al. teaches the use of hydrogenated tallowalkyl 2-ethylhexyl dimethylammonium salts dissolved in water and/or ethanol or in isopropanol in fabric softener compositions. These compositions are clear because they form true solutions.
While consumer preference favors clarity in fabric softener compositions, fabric softeners are preferably brought into contact with the fabric as macroemulsions.
It is an object of this invention to provide a clear liquid fabric softener composition that is environmentally acceptable.
It is another object to provide such a fabric softener composition as an aqueous microemulsion concentrate.
It is also an object that this microemulsion composition be physically stable for at least about six weeks.
Another object is to provide a microemulsion which upon dilution, as in a washing machine dispenser, forms a macroemulsion without gelification.
Other objects will become apparent to those skilled in the art upon a further reading of the specification.